1. Field of the Invention
The present invention relates to a communication device. More particularly, the invention relates to a car-mounted information device, which makes it possible to obtain information (present positions, destinations, etc.) of the transmitting source and of the receiving end linked to a navigation function relying upon the end-to-end communication by using electronic mail among vehicles.
2. Description of the Related Art
Cellular phones have heretofore been used for exchanging and confirming information related to the present positions and destinations between a driver of a vehicle and a driver of another vehicle. While the vehicles are traveling, however, it is not allowed to use the cellular phones from the standpoint of preventing accidents, which is inconvenient for the drivers.
Owing to rapid progress and development of communication technologies as represented by the widespread use of the Internet in recent years, however, automobile manufacturers and related manufacturers are now building up an information service network for offering information for vehicle-mounted information devices. The automobile manufacturers are establishing information-providing companies on the basis of a charged membership system, and are providing a variety of information such as traffic information, news, weather forecasts, electronic mail, internet information, etc. to the members through an information center.
FIG. 1 schematically illustrates the above information service network system.
In FIG. 1, a vehicle 1 has an information device mounted therein which has a car navigation function and a cellular phone function, and provides access to an information center 3 through a communication network 2 constituted by a cell phone network or the like. In response to a request from the vehicle 1, the Information center 3 offers an internet service, such as traffic information, electronic mail, web surfing, etc. linked to the car navigation function.
In driving the vehicle as described above, however, it is not allowed to exchange information by speech through the cellular phone. With the system in which the automobile manufacturers offer information, further, there remains a problem from the standpoint of cost such as monthly fees due to the charged membership and fees for communication, in addition, information that is available is limited to the information possessed by the information center 3. Therefore, the driver driving the vehicle is not allowed to obtain information which he wishes to obtain at present in real time, such as present position of another vehicle, traveling conditions or traffic information, leaving a problem from the standpoint of the content of information.